Field of the Invention
This invention relates in general to rules for measuring, and it deals more particularly with a thin rule of the portable type such as might be carried around on the job by a workman in a small pouch or in his pocket.
The invention is directed toward a level system for a small thin rule which can be inserted with the leveling device into small spaces.
With the advent of miniaturization in modern devices of all types there is a tendency to assemble structures in as compact a space as is possible under the individual circumstances. Many of these compacted structural parts must be assembled in a level position in order for the device to work properly.
One application of this type of assembly can be found in the common electrical industry or in the wiring of electrical components for building structures, where thermostats and gravity switches may be installed in a very confined area. For the switch to operate in a normal mode its housing box should be installed in a level position, since all of the other components of the switch are relatively installed at adjustable angles to the housing.
Heretofore, combination levels in connection with measuring devices have neglected the demands of miniaturization. The devices which have been provided might have been attached to or a part of a thin rule or measuring device, but the leveling devices themselves were not intended to be inserted into confined spaces.
After competent search, no existing devices of the type disclosed in the present invention were found, there being six references which were considered, but which do not appear to conflict with the present invention or anticipate either the apparatus or the objects and purposes for which it was designed.
The prior art discloses the following U.S. Pat. Nos.:
G. L. Finstrom, 1,338,176 PA1 J. C. Alford, 3,145,475 PA1 D. E. Wright, 3,328,887 PA1 U. Tuomi, 948,777 PA1 W. Chalupny, 1,848,003 PA1 J. T. Sherwin, 149,532
The Finstrom, U.S. Pat. No. 1,338,176 shows a collapsible extensible rule having a combination of bubble levels to be read both in the vertical and horizontal position. However, it will be noted from this patent, which was issued in 1920, that the sections 17, 18, 19, 20, 21, 22, 23, 24, 25 and 26 are stacked within the case 30 and are extensible and interlocking in order to form a long length of rule which may be used for the purpose of measuring. The bubble level system in this instance is not an integrated system and they are contained in the case 30 which houses the extensible rule. There would be no manner in which this patent could teach the thrusting of the end of a thin rule containing a level system into a confined space. The entire handle housing in this patent would have to be employed in order to utilize the level.
The Alford, U.S. Pat. No. 3,145,475 shows a measuring and marking device. This does not relate to a thin extendable or a collapsible rule at all, but shows a handle which is attached to the measuring and marking device, which handle contains both a horizontal and a vertical level bubble adjacent to the rule. There would be no way in which this patent could teach a system which could be adapted to a thin rule and placed within a confined space.
The Wright, U.S. Pat. No. 3,328,887 shows a layout tool which could be considered in the same capacity as the extensible rule of the first patent mentioned above. However, this tool discloses two watch face type levels, one which is for a vertical reading and the other for a horizontal reading, contained one above the other, along the line of the rule and recessed into the face of a relatively thick rule which obviously could not be placed in a confined space for the taking of measurements or reading a level. Neither are these units integrated into a single unitary formable unit.
The Tuomi U.S. Pat. No. 948,777 shows a combined carpenter's tool which could not be designated as a thin rule. There is no combined form unit or structure containing both levels and they appear to be in a rather thick section of the rule disposed in the center of the thickness of the rule. Although it is not merely a matter of degree in the disclosure of this patent, it is one which is directed to a device used for laying out door and window casements which are considerably larger than the confined spaces to which the present invention is adapted.
The Chalupny U.S. Pat. No. 1,848,003 shows a rule wherein the levels are adjacently located. One of these could be read from either direction. However, there is not an integral unitary formation with a collapsible or a thin rule which might be inserted into a confined space. This patent has the levels located in such position that it is obvious that it would not suggest the insertion of the levels themself into any confined space.
The Sherwin U.S. Pat. No. 149,532, shows an extensible sliding rule with the formation of the levels in the rule. Again, this patent is not directed to a thin rule, but rather to the technical aspects of a tongue and groove device whereby the rule may be extended upon itself and which would not lend itself to the type of assembly of system of levels which we have in the present invention. It will be noted that the levels are located in the thick part of the rule and do not suggest the insertion of the levels themself into any confined space or teach any of the characteristics of the objects and features of the invention.
Hence, it can be easily seen that none of the prior art teaches any system which would be obvious to one skilled in the art such as to suggest the system employed in the thin rule in the present invention.